1. Field of the Invention
The subject invention in its various aspects relates to airborne video display systems, apparatus for transducing information relative to an information carrier, airborne systems for reproducing recorded video signals, and apparatus for cooling rotary electromagnetic equipment.
2. Description of the Prior Art
In recent years, many airplanes have been provided with motion picture projecting equipment for entertaining passengers during longer flights. In parallel to this endeavor, attempts have been made to provide passenger entertainment with the aid of electronic video display systems operating with video programs received over the air or reproduced by a video tape recorder or playback machine.
Prior-art attempts in the latter area have been sporadic and unsuccessfull from a long-term point of view. In particular, such attempts manifested a prejudice in the art to the effect that electronic video entertainment systems could not be operated with electric power of the 400 Hz frequency typically found aboard aircraft in their power supply. Accordingly, such video entertainment systems employed 60 Hz equipment and bulky frequency conversion apparatus for changing the 400 Hz power supply frequency to a 60 Hz operating frequency. This considerably added to the bulk and weight of the equipment and rendered such systems unacceptable in many airborne applications.
Further problems arose from the fact that existing video tape recording and playback equipment was awkward in its operation and required more attention from the flight personnel than their other duties permitted.
Another reason for the lack of success of such equipment arose from the fact that there was no reliable device for indicating to service personnel the state of wear of delicate parts, such as the video recording and playback heads. Accordingly, there were frequent breakdowns.
Another drawback arose from the entrenched belief that a high-quality video display system could only be realized with display apparatus comprising professional or institutional grade video monitors. The high price, bulk and weight of such equipment rendered its use out of the question in most practical applications.
A further drawback arose from the manifest inability of prior-art equipment to meet safety standards set by aviation authorities. Especially the heat generation problem proved cumbersome as existing cooling equipment was incapable of providing an acceptable solution.